[RickyG]

I dont think my response is as clear cut as joe's. if you consider what he could be calling and not raising with on the flop, I wouldn't put him on a hand on which the 4 helped him.

This is one of those hands where knowing your opponent is huge. I doubt most people would slowplay a set here. While against some trickier opponents you might get slowplayed, I dont know if this is the kind of flop they would do it on with plenty of draws out there.
Therefore, my assumption is that the 4 helped you more than it helped him. With that in mind, I think I might check here.

Lets say on the flop he had some sort of monster draw:
8[img]/images/graemlins/spade.gif[/img] 9[img]/images/graemlins/spade.gif[/img] t[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/diamond.gif[/img]

against your hand he was a 73% favorite, but after this turn, he is a 45% dog in the hand.

This improvement on your hand is true on all draws that do not include a 4, or middle or top set.

The key piece of information for me here would be how likely you are to put this particular foe on a slowplayed set. If he has a 4, there is a good chance that you have higher diamonds and some outs incase you made the wrong choice.

I like gambling, and this is a position I might choose to gamble. If he just calls your bet, and a safecard comes on the river (2c or a diamond), I will probably check call as more hands I can beat will bet out on the river, and no hands I can beat will call, but i might have also chosen to check-raise this turn.

NOTE: I just realized i never submitted this but rather left it in the preview pane. I'd still like some comments on this analysis.